The present invention relates to radio frequency phase shifters and more particularly to such phase shifters for millimeter wavelength signals.
A technology which has been found useful in the millimeter wave frequency range (30 GHz to 300 GHz) is known as fin-line. A fin-line structure comprises a rectangular waveguide having a dielectric substrate therein oriented parallel to the E-plane of the waveguide and extending between the waveguide's lateral walls. The E-field of a fundamental mode wave within a waveguide is parallel to the E-plane.
A conductive layer comprising one or more separate conductive members is disposed on the dielectric substrate. Generally each conductive member is in electrical contact with at least one lateral wall. Since the conductive layer is in contact with the lateral wall it behaves electrically as a ridge or fin within the waveguide.
Radio frequency radar and communication systems which operate in the millimeter wave frequency range are desired. A number of different components needed for the construction of such millimeter wave systems operating at up to about 100 GHz are presently being developed. Many such systems will require compact, propagation control devices such as electrically controllable phase shifters having low loss and low phase variation over a substantial operating frequency band.